Could consider offering to be hired as a consultant.

Pete Muller said of his quants, "I want their shower time because in the shower they are thinking about things that get them to solve the problems." Put another way, in certain roles >50% value is created in 20% office time spent crystalizing ideas developed outside the office.

If your team can capture the >50% value of 20% time for 20% comp, that's a huge win. Assumes your work is qualitatively different from a new hire's. Not "more widgets with fewer defects in less time". If latter, company may reasonably prefer new hire who can put in the 50 hour slog. And you will too, it's no fun working as a time-metered widget-making FTE stand in.